Means and method for dispersing matter in manufactured material



Jan. 7,1936. w. WCARTER 2,027,090

MEANS AND METHOD FOR DISPERING MATTER IN MAIiUFACTURED MATERIAL PatentedJan. 7, 1936 UNITED STATES MEANS AND M THOD FOR. msrnasmc MATTER mMANUFACTURED MATERIAL WilliamW. Carter, Needham, Mass., asslgnor toBrayton Morton, Fall River, Mass., trustee Application June 30, 1930,Serial No. 464,824

Renewed March 5, 1934 18 Claims.

10 persed condition in a manufactured product a substance which, byreason of its adhesiveness or similar qualities, would be liable toadhere with detrimental efiect to parts of the machinery used in makingthe product, and, second, that ofdisl6 tributing through and retainingin, a product which is made by assemblage of particles suspended in aliquid vehicle, particles or elements of different specific gravitywhich would, without assistance, normally tend to concentrate in astratum instead of being distributed throughout the mass of the product,or would otherwise tend to leave the-product with the liquid vehiclewhen the latter is drained off. The general objects are to preventclogging and other objectionable effects on the manufacturing apparatusby the dispersed matter when such matter is of an adhesive nature toinsure effective distribution of the dispersed matter through theproduct being manufactured;

and to avoid waste and loss of this material in 30 the course of themanufacturing process.v

The invention is a generic one applicable in the.

color effects, etc. I can best explain the nature of the invention bydescribing its application to a particular illustrative use, and forthat purpose in the presentspecification I will choose its ap- 45plication to paper making, particularly paper impregnated with phenolicresin, and compressed dielectric panels made of such paper for radioapparatus. This, however, is by way of illustra-f tion and notlimitation. 50 In the paper manufacturing industry it has long beenrecognized as desirable to incorporate into the fundamental structure ofthe fabric, by introduction into the beater or Hollander, wherein thepaper stock is prepared, large quantities M materials. of a gummy orsticky nature, such as latex, tars,.resins, soaps, glues, casein, andthe artificial or synthetic substitutes for these natural products. Manyand various processes for doing so have been suggested, or bothsuggested and patented, and to some extent successfully used. Theseprocesses generally consist in introducing into the beater the desiredmaterial in the form of an emulsion produced by mechanical means, or byphysico-chemical means with the aid of suitable emulsifying substances,and then beating the pulp and emulsion together and sometimes breakingup the emulsion or precipitating its suspensoid by suitable electrolyticagents, and passing the resulting mixture to the paper forming machines.

These processes have serious objections. One is the adhesion of thesticky, added material to the surfaces of piping, pumps and containersand to the screens, felts and rolls of the paper making machinery, withthe result of clogging the screens and seriously impeding or stoppingthe paper making process or'otherwise spoiling the product. Otherobjections are that the losses of added material with the waste waterdraining out of the paper are usually very large, the cost of chemicalreagents is high, and in some cases the coagulating or precipitatingelectrolyte used injuriously affects the product, especially if theproduct is made for electrical insulation.

' The object and accomplishment of my inven tion includes the avoidanceand overcoming of these objections. This is accomplished by theproduction of a colloidal dispersion in which the substance desired tobe added constitutes the dispersed phase,.and the continuous phase is acolloid capable of coagulating to a firm gel enveloping the dispersoid.The gel is subdivided into particles small enough to give the properdistribution throughout the paper stock when added thereto in thebeater. Fibers are also bound into the gel in such manner as to protrudefrom the particles into which the gel is divided and form tentaclescapable of'becoming entangled and of felting together with the fibers ofthe paper 45 stock, and of preventing the particles of dispersoid, whichare enveloped in the gel, from being carried away by the waste waterandlost. Such tentacle fibers are introduced intoand distributedthroughout the liquid used to make the 50 colloid dispersion whichbecomes the continuous phase, before coagulation of the colloid. Theymaywith equal effect be introduced into the material constituting thedispersed phase, but practical and mechanicalconsiderations make itrelatively to the strength of the gel, they pull out of the particles inwhich they are but slightly encased and remain attached to thoseparticles in which they are more firmly or more deeply embedded. Theresult is that most, if not all, of the small separated gel particlescarry each one or more fibers projecting at one or both ends beyond itsboundaries in condition to be caught by the wire of the paper machine,or to become entangled with the fibers of the main material in themixture to which these prepared particles are added, so that loss of theparticles by passing through. the screens or otherwise being carried offwith the waste water is prevented.

The drawing herewith provided shows in Fig. l a section of coagulatedgel greatly magnified;

Fig. 2 shows a, separated gel particle still further magnified.

In both figures, a represents the colloid, the black dots designated brepresent particles of the dispersed phase scattered through thecolloid; and the lines represent the fibers. Fig. 2 shows in principlehow after subdivision of the gel the particles thereof contain bits ofthe dispersoid and projecting fiber tentacles. It is not asserted thatevery gel particle will contain a nucleus of the dispersoid and fibertentacles exactly as here depicted. Some particles may divide from themass without containing either, and others may have agreater or lessnumber of particles of dispersoid and a greater or less number ofencased and. projecting fibers; but generally the particles will containone or more globules or fragments of dispersoid and one or more fiberssubstantially as shown. I

In making the specific illustration of the invention previouslymentioned, bakelite paper for the production of radio panels, thefollowing procedure, using materials and proportions as hereinafterstated, is suitable.

100 pounds of dry alpha cellulose is treated with caustic soda andcarbon bisulphid according to the well known method of making viscose.The

resulting sodium thio-carbonate of cellulose is converted into a smoothpaste by the addition of suflicient water to bring the celluloseconcentration to about 15%. Into this solution is run slowly andstirredrapidly about 800 pounds of the A form of the phenol-formaldehydecondensation product. This is the viscid solution which settles from theliquid in the wet process of making bake- -lite. When' the dispersion ofthe phenolic resin is substantially complete and uniform, water conetaining 2% of well beaten sulphite wood pulp fibers in suspension isadded, slowly and with rapid stirring to the amount of about 1200pounds.

, This mixture is then allowed to gel naturally, or

gelling may be hastened by careful heating to a temperature of about 70C. or slightly more. The resulting gel is aged until it begins to throwout water and is firm enough to hold together when dumped from thecontainer. In this condition the gel is a solid, containing water, butnot soluble in water or subject to disintegration by thea'ction of wateralone, and it is not sticky. But

it is attached or bonded with considerable firmness to the fiberscontained within it; and forms anenvelope for the sticky dispersoidwhich prevents the latter from adhering to anything. This productconstitutes an embodiment of the colstrength for the purpose.

.preferable in most cases to introduce them independently into theliquid as first above stated.

loidal dispersion, containing a dispersoid and scattered fibers, of thepreceding general description.

The gel is now introduced into a beater contain-' ing 500 pounds ofpaper stock already well beaten and in which the beater roll is adjustedso as just to brush the fibers. The gel is added slowly while the beatercontinuously operates. In a period ranging from half an hour to one hourthe gel becomes divided into fine particles which are 10 dispersedsubstantially uniformly through the pulp mixture, these particlesconsisting of the viscose colloid enveloping, or encysting, globules ofphenol resin and carrying protruding fibers.

The contents of the beater are now delivered to a paper machine and madeinto paper, which is formed and dried in the usual way. In passingthrough the beater and the paper machine, the particles of sticky resinare protected by the envelope of colloidal gel from contacting with thesurfaces of the machinery and sticking to the wire and clogging it. Thefibers protruding from the gel particles retain them in the web of paperbeing made.

After the paper has been dried it is cut to the desired size and anumber of sheets are stacked upon one another sufficient to make afinished panel of the required thickness. This stack is molded underheat and hydraulic pressure in a mold. This treatment causes theparticles of resin to expand and their colloidal envelopes to becrushed; actions which together liberate the fluid resin, which thenspreads and permeates the entire fibrous mass. Panels so made are atleast equal, and generally are superior, to those made by previousprocesses and their cost is substantially less.

It will be understood that the foregoing specific example is not in anysensea limitation to quantities nor even to exact proportions, but is anillustration of the general principle by a concrete example. Even in themaking of this particular type of paper, the process may be carried outcontinuously, with continuous introduction of the colloidal dispersioninto the beater and continuous delivery of the entire mixture to thepaper machine. I v

I have successfully made paper inaccordance with the foregoing example,with complete absence of trouble of any kind due to the sticky phenolicresin. The resin did not stick ,to the beater or itsrolls, or to theassociated piping and pumps; did not clog the wire of the paper machine,and did not adhere to the felts or rolls of the paper machine or drier,or interfere in any way with-the successful formation of the paper weband its passage between the felts and press rolls and through the drier.There was no appreciable'loss of the expensive artificial resin in thewaste water. The molding of the :stack of sheets under hydraulicpressure and heat was successfully accomplished and produced amechanically strong and electrically excellent dielectric of low powerfactor.

- For general use in paperdnaking, as well as in the particular examplegiven, a viscose cellulose is practical and satisfactory forthecolloidal dispersion, as it is inexpensive, gels naturally, and onregeneration reverts to a cellulose of the same nature as the paperitself and has sufficient However, I am not limited in this particular,for other compounds and substances may be used-for the continuous phasein the making of paper and other prod-.-

ucts according to this invention. For instance.

30 the scope of this invention.

the continuous phase may be othercellulose products than viscose, orother organic compounds such as albumen, glue, casein, starch, etc. Thecoagulation of the gel may be allowed to occur naturally or may beproduced or hastened artifically by application of heat or use of aspecial agent, as formaldehyde or an acid, the particular agent beingdetermined for the particular material used in the continuous phase by10 the known requirements under physico-chemical laws for coagulation ofthe. colloid to the gel form It is not essential that the gel beintroduced into the beater immediately after coagulation and while stillholding a large content 15 of water. Its characteristics are such thatit does not'deteriorate by aging, or sufier any change except loss ofwater through drying; and after drying it will take up water again.

The fibers dispersed through the continuous 20, phase for anchoring thegel particles may be of widely various characters. In paper making theyare generally and preferably fibers of the same pulp stock of which thepaper is made, but not necessarily so. They may be any fibers of vege-25 table, animal or mineral origin,- and of natural or artificialstructure, as wood, cotton, linen, wool, silk, hair, rayon, asbestos,metallic wire, etc. Artificial filaments are thus included within thecategory of fibers for the purposes and within Fibers of specificmaterials are selected, and may be colored, for ornamental effect,-strength, or other desirable effects. Metal fibers may be used, when theelectrical conductivity or the color appearance, 35* strength, hardnessor other qualities characteristic of metals are desired.

For some purposes the combination of fibers and gel particles alone maybe used without any nucleus of dispersoid in the gel particles, as in 40cases where the fibers themselves are the desired added material. Insuch cases the gel particles attached to the fibers act as buoys orfloats when the fibers are of high specific'igravity, preventing themfrom settling out of the main mixture q in a concentrated layer.

The dispersoid may. be any liquid, 'or solid granular or powdered,material which for any reason it may be desired to combine in dispersedcondition with any -manufactured product. In

5Q the class of liquids. and semiliquids are included natural orartificial substances as tars, bitumens, gums, waxes, resins, oils,soaps, latex or other rubber dispersions, etc. Solid dispersoids includesuch matters as insolublepigments and dyes, abrasives, mineral fillers,etc. For instance, an abrasive paper superior to sandpaper, emery clothand the like may be made by adding to the paper stock grit in the natureof sand, emery, carborundum or the like dispersed- 60 and incorporatedas taught by this invention.

I have endeavored by the last preceding paragraphs to indicate the widescope of the invention without attempting or intending to give an.

exhaustive listof the manufactures which may 65 be made and thematerials which can be dispersed through them, or thecolloidalsubstances and fibers which may be used to efiect dispersionand retention of the added matters in the products, according to thisinvention. In general 7 any manufacture which at an unfinished stage isin a liquid state, or in a condition of liquid suspension, capableofhaving added materials disseminatedthrough its mass is within the rangeof products producible by the invention. Any

75 material, capable of being dispersed through the the substance of themain product.

liquid which is to become a gel, may be combined in the product as thedispersed added material. Any gel material capable of receiving adispersoid before coagulation may be used, with this proviso, that thematerial must produce a gel of such strength and nature that it willpersist as a gel when incorporated in the main mixture. Of courseneither the gel material nor the added material should be of a nature toinjure the main mixture. 10

, The gel associated with either a nucleus of dispersoid or with anchorfibers, or with both, constitutes a mechanical operator or tool by meansof which the added matter is brought into Combined with a. nucleus, thegel particle is a mechanical operator which brings a chemical substanceinto the main product and protects or insulates such substance from themachinery and vice versa. In association with fibers, the gel particlesare in some cases buoys or floats for the fibers and in other cases thefibers are anchors which retain the gel particles in the unfinished mainproduct. The gel particles are usable in three forms, as (a) thecomplete combination of the gel particle with its enclosed nucleus ofdispersoid and at tached fibers; (b) the gel and nucleus; or (c) the gelparticle and attached fiber. These combinations I desire to protectbroadly and specifically in all the applications and associations wherethey are useful. From one point of view, the gel particle in itsassociation with a nucleus and a fiber constitutes a binder attachingthe nucleus to the fiber, thereby performing a function' additional toor independent of that of insulating the nucleus against possibility ofadhering to the surfaces of apparatus.

What I claim anddesire to secure by Letters Patent is:

l. The method of incorporating added material in dispersed conditionthroughout a fibrous prodnot of manufacture which consists in firstattaching separated particles of the added material with fibers, so thatends of fibers project from such particles, mixing said fibers andattached particles of added material with the fibers of the mainmanufacture in liquid suspension and separating the liquid vehicle fromthe mass of mixed fibers so that the fibers which carry attachedparticles become felted with the fibers 5d of the main mixture.

2. The method of distributing fibers throughout the mass of a product incourse of manufacture which consists in first distributing such fibersthroughout a body of gel forming liquid, breaking up the gel resultingfrom coagulation of such liquid into particles smaller than the lengthsof such fibers, and mixing the particles of gel with attached fibersthroughout the main material of the manufacture in liquid suspension,and subsequently separating the liquid vehicle from the resultingmixture.

3. The method of incorporating an added material in dispersed conditionin paper which consists in first attaching encysted particles of thedispersoid to fibers of a length sufiicient to interlace with the fibersof paper pulp, apart from the after-mentioned furnish, then mixing thefibers and their attached particles of dispersoid with a paper pulpfurnish, and forming the fur- Irish with such admixture into paper.

4. The method of incorporating in distributed condition in paper, fibersof a different character from the paper fibers, which consists inattaching to such added fibers, apart from the after-mentioned furnish acolloid which is assimilable with the stock of which such paper is made,separating such colloid into particles with attached fibers and mixingthe same with a paper pulp furnish, and forming the furnish mixture intopaper.

5. The method of incorporating an added material in paper which consistsin dispersing the material to be added through a body of liquidcellulose viscose, coagulating the viscose into a gel, subdividing thegel into particles containing nuclei of the dispersoid, mixing the gelparticles with a paper pulp furnish, and forming the furnish mixtureinto paper. a

6. The method of making paper containing an added material in dispersedcondition therein which consists in dispersing the added materialthroughout liquid viscose cellulose, distributing fibers of paper pulpthroughout the viscose, coagulating the viscose, separating thecoagulated gel into particles containing nuclei of the dispersoid andpulp fibers, distributing the particles throughout a paper pulp furnish,and forming the furnish mixture into paper.

'7. The method of preparing matter for dis persion within a manufacturedproduct which consists in mixing separated particles of such materialthroughout a body of coagulatablecellulose gel forming liquid so thatsuch material becomes the dispersed phase of a colloidal dispersion inwhich the coagulated gel is the continuous phase, and permitting the gelto coagu late before incorporation in the product.

8. The method of preparing material for distribution within amanufactured product, which,

consists in mixing separated particles ofsuch material throughout'a bodyof liquid adapted to coagulate into a gel, also mixing through suchliquid fibers of substantially greater length than the particles of thedispersoid, and permitting the gel to coagulate prior to incorporationin the product.

9. A colloidal dispersion for use in distributing a sticky materialthrough a product in course of manufacture, comprising a colloidal gelas the continuous phase, adapted to be broken into discrete,non-unitable particles, separated particles of the mat'erial to be addedconstituting the dispersoid, and fibers of substantially greater lengththan the dimensions of the dispersoid distributed in non-feltedseparation from one another throughout the gel.

10. The method of manufacturing a product containing a differentsubstance dispersed through its mass which consists in distributing thematerial to beadded in dispersed condition throughout a gel formingliquid, subdividing the solid gel coagulation of such liquid intodiscrete particles containing particles of the dispersoid, and mixingthe gel particles inv liquid suspension with the material of the productin course of manufacture.

11. The method of incorporating an added material into a papermanufacture which consists in dispersing particles of such addedmaterial throughout a body of gel forming liquid; dividing the solid gelresulting from coagulation of such liquid into discrete particlescontaining bits of the dispersoid, mixing such gel particleswith paperstock in liquid suspension, and forming the resultant mixture intopaper. 5

12. The method of incorporating added material in paper which consistsin distributing the added material in small particles throughout a bodyof gel forming, liquid, mixing fibers in dispersed condition through theliquid, allowing the liquid to coagulate into a gel and to age until itis firm enoughto cohere when removed from its container, separating thecoagulated gel into particles containing nuclei of the dispersedmaterial and fibers protruding from said particles, mixing suchparticles with a paperupulp furnish, and forming the furnish mixtureinto paper.

13. The method of incorporating fibers or strands of other material thanpaper pulp fibers throughout paper, which consists in distributing 20such fibers in separated condition through a gel forming liquid which isassimilable with paper, coagulating such liquid into a coherent gel,subdividing the gel into particles smaller than the length of suchfibers so that the fibers protrude 25 from the particles, mixing thefibers with their attached gel particles throughout a paper furnish, andmaking the furnish mixture into paper.

14. The method of adding dispersed matter to a fibrous product whichconsists in first mixing 30 fibers and dispersed added material with agel forming liquid, allowing the liquid to coagulate into a gel, andthen breaking up the coagulated gel into particles containing andenveloping the said added material, such particles being generallysmaller in dimensions than the fibers so that ends of such fibersproject from them, and mixing the broken-particles with the stock of themain product in liquid suspension and forming the resulting stockmixture into the end product, with extraction of the liquid ofsuspension therefrom.- 1 g 15. A paper manufacture comprisingintermingled fibers substantially free from attached masses or films ofadded substances, and other fibers interlaced with the first namedfibers and having in attached connection with them particles of addedmaterial encysted in colloidal envelopes.

16. A paper manufacture containing in distributed condition within itsmass, particles of a different material bound into the paper byinterfelting with the fibers thereof of other fibers to which the saiddifierent material ,is attached.

17. A manufactured product consisting of interlaced and felted fibers,discrete particles of extraneous matter encysted in colloidal gel boundto certain offset fibers, and other fibers being free of such attachedparticles.

18. A paper product comprising interfelted fibers and particles of gummaterial encased in solid non-sticky colloidal envelopes and attached toscattered fibers of the mass in such manner as to leave the productsubstantially open and porous;

